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| n | a(n) |
|---|---|
| 4 | 6 |
| 5 | 30 |
| 6 | 105 |
| 7 | 315 |
| 8 | 868 |
| 9 | 2268 |
| 10 | 5715 |
| 11 | 14025 |
| 12 | 33726 |
| 13 | 79794 |
| 14 | 186277 |
| 15 | 429975 |
| 16 | 982920 |
| 17 | 2228088 |
| 18 | 5013351 |
| 19 | 11206485 |
| 20 | 24903490 |
| 21 | 55050030 |
| 22 | 121110297 |
| 23 | 265289475 |
| 24 | 578813676 |
| 25 | 1258290900 |
| 26 | 2726297275 |
| 27 | 5888802465 |
| 28 | 12683574918 |
| 29 | 27246198378 |
| 30 | 58384711245 |
| 31 | 124822486575 |
| 32 | 266287971856 |
| 33 | 566935682544 |
[6,30,105,315,868,2268,5715,14025,33726,79794, 186277,429975,982920,2228088,5013351,11206485, 24903490,55050030,121110297,265289475,578813676, 1258290900,2726297275,5888802465,12683574918, 27246198378,58384711245,124822486575,266287971856, 566935682544] |